1. Field of the Invention
The present invention relates to a press-connecting terminal used in the wiring in a vehicle. More particularly, the present invention relates to a structure of pairs of press-connecting blades which can rapidly and positively grip and electrically contact any one of electric wires of various sizes to be press-connected to the press-connecting terminal.
The present application is based on Japanese Patent Application No. Hei. 11-231785, which is incorporated herein by reference.
2. Description of the Related Art
In a vehicle having various electronic equipment mounted thereon, press-connecting terminals have been extensively used in the connection between the electronic equipment and in the connection between electric wire harnesses. One known conventional press-connecting terminal 30, shown in FIGS. 7 to 11, includes a connection portion 31 for connection to a mating press-connecting terminal (not shown), a press-connecting portion 32 of an upwardly-open channel-shaped cross-section for press-connection to an end portion of an electric wire 21, and barrel portions 33 for clamping or gripping the electric wire 21. A resilient contact piece portion 35 is provided within the connection portion 31, and the mating press-connecting terminal, inserted into the connection portion 31 through an insertion opening 31a formed in a front end thereof, contacts this resilient contact piece portion 35. A lance 36, formed on an upper surface of the connection portion 31, serves to retain the press-connecting terminal against withdrawal when the press-connecting terminal is inserted into a connector housing (not shown). A stabilizer 37 serves to control the direction of insertion of the press-connecting terminal.
The press-connecting portion 32 includes two pairs of front and rear press-connecting blades 41 and 42. As shown in FIG. 10, the front press-connecting blades 41 are formed by inwardly bending a pair of stamped-out piece portions 44 of opposed right and left side plates 39 of the press-connecting portion 32, and a press-connecting groove 45 is formed between the pair of piece portions 44. The width of the press-connecting groove 45 is smaller than the diameter of a conductor 23 of the electric wire 21. FIG. 10 is a cross-sectional view taken along the line X--X of FIG. 9.
As shown in FIG. 8, the rear press-connecting blades 42 are formed by stamping out a relevant portion of a bottom plate 47 and then by bending this stamped-out portion upwardly in perpendicular relation to the bottom plate 47. The rear press-connecting blades 42 are spaced a predetermined distance from the front press-connecting blades 41. As shown in FIG. 11, a press-connecting groove 49 is formed between the pair of press-connecting blades 42, and the width of this press-connecting groove 49 is equal to the width of the press-connecting groove 45. FIG. 11 is a cross-sectional view taken along the line XI--XI of FIG. 9.
Next, the process of press-connecting the electric wire 21 will be described. The end portion of the electric wire 21 is press-fitted toward the press-connecting blades 41 and 42 from the upper side of the press-connecting portion 32 as indicated by an arrow in FIG. 7. As a result, opposed side edges of the press-connecting groove 45, formed between the press-connecting blades 41, and opposed side edges of the press-connecting groove 49, formed between the press-connecting blades 42, cut a sheath 22 of the electric wire 21, so that the conductor 23 of the electric wire is brought into contact with the side edges of these press-connecting grooves 45 and 49, as shown in FIGS. 10 and 11. Then, the electric wire 21 is clamped by the pair of barrel portions 33 through the sheath 22, thus completing the fixing of the electric wire 21 to the press-connecting terminal 30.
In the case where the electric wires 21 to be used have various diameters, that is, their respective conductors 23 have different diameters, the press-connecting terminal 30 can not be suitably used for all of these electric wires 21 of different diameters since the width of the press-connecting grooves 45 and 49 is fixed, and therefore there has been encountered a problem that there have been needed various press-connecting terminals each for exclusive use with the electric wire 21 of a particular diameter.
Particularly, unless the conductor 23 is adequately press-connected to the press-connecting blades 41 and 42 of the conventional press-connecting terminal 30, a contact electrical resistance at the press-connecting position increases, and as a result problems, such as the generation of heat, have been encountered. In order to prevent such problems, it is necessary to prepare many kinds of press-connecting terminals having the respective press-connecting grooves whose widths correspond to the electric wires 21 of various sizes, respectively. However, this is obviously disadvantageous from the viewpoints of the material control, the processing of the parts, the assembling operation, the maintenance and so on.